In:
Journal of Materials Chemistry A, Royal Society of Chemistry (RSC), Vol. 10, No. 41 ( 2022), p. 22257-22270
Abstract:
Among the alkaline earth-based perovskite oxides, the Ba-based perovskites have superior chemical stability and tunable electrical/catalytic property via chemical substitution/doping. One of the best-known examples is Ba 3 Ca 1.18 Nb 1.82 O 8.73 as a ceramic proton conductor for all-solid-state steam electrolysis and solid oxide fuel cells (SOFCs). Structural ordering variation is often driven by chemical composition, which directly correlates with their chemical/physical properties. In the present work, we develop a comprehensive functional perovskite-type phase diagram for the Ba–Ca–Ta–O quaternary system Ba 3 Ca 1+ x Ta 2− x O 9−3 x /2 (0 ≤ x ≤ 0.36) with a wide chemical composition between 1000 and 1550 °C, coupled with theoretical calculations to investigate the cation ordering in supercells. Furthermore, the impact of cation clustering on the diffusion pathways of O 2− ions was evaluated as a case study. Experimentally, precise cation ordering and other structural features are quantitively determined by TOF-neutron and synchrotron X-ray diffraction analyses. This work provides a comprehensive evaluation of some potential applications of the Ba–Ca–Ta–O quaternary system. The electrochemical impedance data were also systematically studied by impedance spectroscopy genetic programming (ISGP). The electrical conductivity was found to increase from x = 0 to x = 0.27 and then decrease for the end member when x = 0.36 due to a decrease in mobile charge carrier concentration. Interestingly, in dry air, the electrical conductivity was found to increase from x = 0 to x = 0.36. However, only Ba 3 Ca 1.18 Ta 1.82 O 8.73 (BCT18) and Ba 3 Ca 1.27 Ta 1.73 O 8.595 (BCT27) were found to show an increasing trend in conductivity in humid atmospheres, and this indicates that the clustering effect was pO 2 dependent.
Type of Medium:
Online Resource
ISSN:
2050-7488
,
2050-7496
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2022
detail.hit.zdb_id:
2702232-8
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